Headlamp dimmer system



vMarch 26, 1957 M. L. WOODWARD HEADLAMP DIMMER SYSTEM Filed Feb. 3, 1.956

70 1/6? 577/767! 4 144 0 Pan 5e JUPPZ SENSITIVE I nve ntor Attorney HEADLAIVIP DIMMER SYSTEM Myrneth L. Woodward, Lapel, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February 3, 1956,Serial No. 563,348 4 Claims. (Cl. 315-83) This invention relates to automatic switching means and more particularly to automatic timed switching control means adapted to be connected to light controlled multi filament lamp circuits to introduce a distinguishing or characteristic flash of the lamps.

Many highway vehicles having the conventional high and low beam filament headlamps are currently also supplied with automatic light sensitive control means to switch from high beam to low beam illumination upon the approach of a vehicle from the opposite direction and return to high beam when the vehicle has passedf This action is ordinarily accomplished manually by the driver. It would be advantageous to advise the approaching driver as to when the vehicle was equipped with automatic light control means for switching from high to low beam.

It is therefore an object in making this invention to provide means for advising the approaching driver whether the headlamps are under manual or automatic control.

It is a further object in making this invention to provide means for introducing a characteristic or distinguishing flash in an automatic headlamp dimming system to advise the approaching driver that the car is equipped with automatic dimming apparatus.

It is a still further object in making this invention to provide an automatic control system whereby only one headlight filament is initially deenergized, followed by a later delayed deenergization of the second filament to cause a winking or blinking characteristic identifying signal.

With these and other objects in view which will become apparent as the specification proceeds, my invention will be best understood by reference to the following specification and claims and the illustrations in the accompanying drawings, in which:

The figure is a circuit diagram of a control system embodying my invention.

Referring now more particularly to the figure, there is shown therein two headlamps having bright filaments 2 and 4 and dim filaments 6 and 8 respectively. The center tap between the bright and dim filaments is grounded in each case. Line 10 extends to the power supply for the vehicle and is connected to one terminal of a relay operating coil 12 and also to the armature 14 controlled thereby. Armature 14 oscillates between two stationary contacts 16 and 18 and engages contact 18 when the operating coil 12 is energized. Contact 16 is connected through line 20 with one terminal of the bright filament 2. Contact 18 is connected through line 22, and tie line 24 connected thereto to one terminal of each of the dim filaments 6 and 8.

A light sensitive control dimming unit 26 is connected to and controls a sensitive relay coil 28. When no light falls on the light sensitive control system, the relay coil 28 is energized. Alternately, when sufficient light falls on the light control system, the relay coil 28 is deenergized. An armature 30 whose position is determined by the coil 28 is grounded and is adapted to engage a stanited States Patent 0 Patented Mar. 26, 1957 tionary contact 32 when the coil 28 is deenergizcd. Contact 32 is connected through line 34 to the remaining terminal of the relay coil 12. p

A flasher unit 36 consists of a magnetizable core 38 around which a magnetizing coil 40 is wound, together with two armatures 42 and 44 pivoted at their lower extremity and movable toward the core. Armature 42 is of magnetizable material and is moved to the left of the position shown in the figure when magnetizing coil 40 is energized. On the other hand armature 44 is of nonmagnetizable material and is moved inwardly due to any suitable mechanical bias, but held away from the core 38 by a hot wire element 46 which expands upon heating, permitting the armature 44 to rotate clockwise. The upper end of armature 42 oscillates between two stationmy contacts 48 and 50, engaging contact 48 when the coil 40 is deenergized, and 50 when energized. Armature 44, on the other hand, only engages one stationary contact, which is shown at 52, and in its outer position closes no switching means. The hot wire 46 is connected through line 54 with a tie line 56 extending between the two stationary contacts 50 and 52, and is also connected portion of both armatures 44 and 42 and is'connected through conductive line 62 to power supply line 10.

In the operation of this system, if it is assumed that the car is operating on a darkened highway with no cars approaching from the opposite direction, relay coil 28 is energized and holds its armature 30 in its lower position, opening the contact at 32. At this time two separate circuits are completed to the two bright filaments 2 and 4. The first is as follows: from power line 10, through armature 14, contact 16, line 20, bright filaments 2, to ground. The second is from power line 10, line 62', tie line 60, armature 42, contact 48, line 64, bright filaments 4, to ground. As long as no light of sufiicient intensity falls on the light sensitive control unit 26 to deenergize relay coil 28, the system will remain in this condition with the bright filaments illuminated. If now a car light source approaches and the automatic system switches to low beam, relay coil 28 will become deenergized. This causes armature 30 to be pulled away from coil 28 and it will engage contact 32. This completes an obvious energizing circuit for relay coil 12 and it pulls down its armature 14, and as a result breaks the energizing circuit to the bright filaments 2, and they will become deenergized. This, however, has no eifect upon the energizing circuit to the bright filaments 4, and they will stay illuminated or energized. However, the movement of the armature 14 to its attracted position completes an obvious energizing circuit to both of the dim filaments 6 and 8 and they are energized. At this instant there are two filaments energized in one headlamp, namely 4 and 8, and only one energized in the other headlamp, namely dim filament 6.

The completion of the grounding circuit for line 34 likewise completes a series circuit through both the hot wire 46 and the energizing coil 40 of the flasher relay 36. This circuit may be traced as follows: power supply 10, line 62, armature 44, hot wire 46, connecting line 54, relay winding 40, indicating light 58, line 34, contact 32, armature 30, to ground. However, there is sufiicient resistance in this circuit to keep the current in the operating coil 40 of the relay from pulling in its armature 42. Current flow through the hot wire 46, however, causes elongation of the same, and this armature moves clockwise, and within a predetermined time engages stationary contact 52. This provides a shunt circuit across the hot wire and its circuit, reducing the total resistance in the circuit and permitting the coil 40 to attract its armature 42. This action breaks the supply circuit to the bright filament 4, thereby causing a deenergization of these filaments after a predetermined time. The closing of the circuit between armature 42 and stationary contact completes a. holding circuit for the flasher relay coil, and it will remain in this condition until the light sensitive relay coil 28 is again energized.

This system therefore provides a delay in deenergizing one of the bright filaments of a pair of headlights to provide a characteristic winking or blinking indication to the approaching driver that the car is equipped with an automatic, light sensitive dimming system.

I claim:

1. In a switching system, a plurality of electrical lamps having at least two filaments of different value in each, a source of electrical power, switching means interconnecting the source with one filament of equal value in each lamp, separate switching means interconnecting the other filament in each lamp independently to the source of power and time delay means connected to one of said last-named switching means to delay its operation until some time after the other separate switch has operated.

2. In a control system for a plurality of multi filament lamps having filaments of difierent value, a source of electrical power, a first switching means connected between the source of power and two filaments in one lamp and one filament in a second lamp to simultaneously energize one filament of equal value in each lamp or alternately one filament of diiferent value in one lamp, and time delay switching means connected between the source of power and one filament of difierent value in the other lamp to control the energization of the same.

3. In a control system for a plurality of multi filament lamps having filaments of different value, a source of electrical power, a first switching means connected between the source of power and two filaments in one lamp and one filament in a second lamp to simultaneously energize one filament of equal value in each lamp or alternately one filament of diiferent value in one lamp, time delay switching means connected between the source of power and one filament of different value in the other lamp to control the energization of the same, and a light operated master switch in circuit with both the first switching means and the time delay switching means to control the same.

4. In a control system for a plurality of vehicle headlamps having high and low beam filaments, a source of electrical power, first switching means connected to said source of power, commonly to the low beam filaments in at least two lamps and to the high beam filament in one lamp, operating means for the first switching means, light controlled switching means connected to the source of electrical power and the operating means to determine the operation thereof by incident light values, and time delay switching means also connected to the source of electrical power, the light controlled switching means and to the high beam filament in the other lamp to control the energization thereof in timed relation to the energization of the other beam filaments.

No references cited. 

